Antibiotic costs

5.5. Antibiotic costs

It is generally agreed that the use of antibiotics has selected for resistant organisms from initially susceptible populations and further use has encour- aged the subsequent proliferation witnessed today (Schentag et al., 1998). While any antibiotic has the propensity to select for a resistant strain, there are some classes that are more likely to be associated with MRSA (Dancer, 2001; Hill et al., 1998; Hori et al., 2002; Monnet, 1998; Monnet and Frimodt-Moller, 2001; Venezia et al., 2001). The consequence is clinically significant infection with an organism for which there are few treatment options (Dancer, 2003). Those antibiotics, which might be expected to be effective, tend to be expen- sive and toxic (Dancer, 2003; Janknegt, 1997). It is likely that the cost of using and monitoring such drugs for MRSA provide a significant contribution towards overall HAI costs (Casewell, 1995; Rao et al., 1988; Vriens et al., 2002). Conversely, decreasing overall antimicrobial use and/or improving the quality of antimicrobial prescribing might be expected to lower the cost of pharmaceuticals for HAI (Geissler et al., 2003; Landman et al., 1999).

The study by Plowman et al. also examined the antimicrobial costs for HAI (Plowman et al., 2001). Antimicrobials accounted for a mean cost of £13.40 for non-HAI patients, compared to £71.07 for HAI patients. The percentage contri- bution towards the overall costs of HAI was 1.83%. The contribution from antibiotics towards costs of serious S. aureus infection, however, was shown to

be 21% in a separate study (Wakefield et al., 1988). The same study examined antibiotic costs for both MSSA and MRSA, and found that mean costs for MSSA accounted for $612.53 compared with $1067.52 for MRSA. Adverse complications of antibiotic therapy were not investigated, but the authors postu- lated that the requirement for parenteral therapy for MRSA contributed towards the number of additional drugs in hospital for MRSA patients (mean 19.1 days) compared to patients with MSSA (mean 5.9 days) ( p ⬍ 0.004) (Wakefield et al., 1988). MRSA outbreaks also have the potential for driving up drug costs.

A 5-week outbreak involving five wards consumed £6,440 worth of teicoplanin, almost half the total cost attributed to the outbreak excluding labour costs and extra days in hospital (Mehtar et al., 1989).

It seems reasonable to examine the potential for savings from infection con- trol policies and programmes regarding the use of antibiotics (Mehtar, 1993, 1995). The role of the medical microbiologist includes giving advice on antimi- crobial therapy, encompassing choice, dose, length of course, route, toxicity,

The Real Cost of MRSA 295 combinations, and monitoring. Timely and appropriate advice on the manage-

ment of infected patients can contribute significantly towards cost savings. Without microbiological guidance, it was shown that antibiotic usage increased by £2,000 per month, compared with a similar period in the previous year (Mehtar, 1995).

The implementation of antibiotic policies has been shown to be cost- effective (Geissler et al., 2003; Mehtar, 1993). Such policies can be extended to formulary restrictions and physician monitoring (Landman et al., 1999; Woodward et al., 1987). Strictly enforced restrictions for aminoglycosides, cephalosporins, and vancomycin generated combined savings of $2.61 per antibiotic day ( p ⬍ 0.0046) and $34,597 per month ( p ⬍ 0.0003) (Woodward et al., 1987). A retrospective analysis of 322 patients with bacteraemia, treated before and after the onset of controls, revealed that antibiotics were more appropriately used afterwards (Woodward et al., 1987). Another study exam- ined both cost savings and the effect on HAI organisms after the introduction of an antimicrobial-prescribing improvement programme (Frank et al., 1997). Over a two-year period, antibiotic prescribing decreased from nearly 160,000 to 140,000 defined daily doses, with concomitant savings of $280,000 in the first year and $390,000 in the second (Frank et al., 1997). These accompanied significant decreases in the rates of enterococcal and selected Gram-negative bacteraemias and in the rates of MRSA and Stenotrophomonas colonisation and infection (Frank et al., 1997).

Antibiotic consumption is particularly high in the Intensive Care Unit. This offers an opportunity for implementing and evaluating policies designed to emphasize more rational use of antibiotics (Gruson et al., 2000). Implementing such a policy in an 11-bedded ICU over a 5-year period resulted in a significant reduction in MRSA and ceftriaxone-resistant Enterobacteriaceae, while costs showed a progressive decrease from €64,500 to €42,000 in the final year (Geissler et al., 2003).

The requirement for parenteral administration of glycopeptides precipitates the extended hospital stay and associated costs for MRSA patients (Janknegt, 1997). Strategies to circumvent this have been introduced, namely outpatient programmes utilising once-daily teicoplanin administration and earlier switch- ing from iv to oral routes if possible (Janknegt, 1997; Nathwani, 2001, 2003; Neiderman, 2001b). An economic evaluation of linezolid, flucloxacillin and vancomycin in the empirical treatment of cellulitis suggested that use of line- zolid alone would result in a higher overall success rate and would be less costly than vancomycin across the entire spectrum of the patients’ risk of being infected by a resistant pathogen (Vinken et al., 2001).

Other relatively simple policies benefit both patients and budgets (Jewell, 1994; Rubinovitch and Pittet, 2001). A decrease in vancomycin expenditure from $32,000 to $12,500 per year occurred following the introduction of contact

296 Stephanie J. Dancer precautions, isolation, and a hand hygiene programme (Herwaldt, 1999). Even

the targeted application of nasal mupirocin can demonstrate cost savings through the lesser numbers of patients who go on to develop MRSA sepsis (Bloom et al., 1996; van den Burgh et al., 1996). The huge difference in the cost of newer antibi- otics for Gram-positive infections will provide a significant impact in prescribing budgets, should glycopeptide-resistant S. aureus flourish (Muto et al., 2003). The parenteral streptogramin, Synercid ® , and the oxazolidanone, linezolid, cost at least five to seventeen times more than vancomycin (Muto et al., 2003).